Link 16 radio systems or terminals typically utilize a Link 16 military waveform (commonly referred to as JTIDS). The Link 16 military waveform is a complex high performance signal-in-space designed specifically to have high anti-jam capability.
The United States government and its military forces often utilize a Link 16 wireless network to communicate data or information among Link 16 terminals. The information can include tactical, positioning, navigational, and other information utilized by military intelligence and other government institutions. Link 16 transmitters and receivers (i.e., terminals) can be mounted on a variety of platforms, including aircraft, naval ships, or even backpack worn by army personnel.
In general, the information in a Link 16 network is transmitted across the airwaves via radio signals (e.g., at frequencies of 969 to 1206 megahertz), which are encrypted on 51 different channels so only users who possess Link 16 terminals can receive the information. The information can be sensitive information, such as, a tactical picture of battlefield conditions, identification of friends and foes, voice communication, or navigational information. The National Security Agency (NSA) tightly regulates the sale and use of terminals or devices capable of operating with a Link 16 network. Generally, the NSA requires that Link 16 terminals be controlled by U.S. forces or very close allies of the United States to protect encryption techniques utilized in Link 16 networks.
Airborne implementations of Link 16 receivers have generally required upper and lower antennas. The upper and lower antennas have required fully redundant receiving capabilities to recover the data on the Link 16 signal. Fully redundant receiving capabilities (fully redundant receivers) is required because it is unknown which antenna has better reception of the signal.
Conventional Link 16 systems utilize dedicated receivers for each antenna. A distinct receiving unit is typically coupled to each antenna. In addition, each receiving unit often includes two receiving circuits. A voting circuit or other logic is required to select the receiving unit that is receiving the strongest signal.
These conventional systems require redundancy, from the analog receiver front end and its filtering completely through the use of digital correlators to determine which antenna is receiving the strongest signal. The use of two receivers or redundant receiving capabilities significantly increases the costs in airborne radio systems because the cost of the receiving hardware is fully double.
Thus, there is a need for a Link 16 system which does not require redundant receiving architecture. Further, there is a need for a low cost Link 16 receiving system for airborne applications. Yet further, there is a need for a low cost Link 16 system which utilized diversity reception to increase performance. Further still, there is a need for a Link 16 which utilizes a signal channel receiver. Further still, there is a need to use multi-path environments in a Link 16 radio system to achieve cost savings and superior performance.